Hydraulic governor pressure control mechanism



T. B. DILWORTH HYDRAULIC GOVERNOR PRESSURE CONTROL MECHANISM April 4, 1961 Filed Dec. 9, 1957 IN VEN TOR. $97! flak/012% B Y 2,977,762 HYDRAULIC GOVERNOR PRESSURE CONTROL MECHANISM Thomas B. Dilworth, Hinsdale, Ill., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Dec. 9,1957, Ser. No. 701,631

4 Claims. (Cl. 60--51) This invention relates generally to engine governors and particularly to engine governors which rely on fluid pressure as a means of operating and controlling certain leakage or by reason of the various connections for controlling operation of the governor. As'a result when the engine is started there is no fluid pressure immediately available in the governor which may cause overspeeding or erraticengine operation untilthe governor has time to build up its own pressure by operation of the pump. I I

From the foregoing, it will be appreciated that the primary purpose of the present invention is to obtain immediate governor control upon starting of the engine and before the governor has had time to build up its own pressure. The above' purpose has been accomplished by, the addition of an auxiliary accumulator 2,977,762 Patented Apr. 4, 1961 p the auxiliary accumulator 20 to predetermined pressure,

which when the engine, i.e., the engine governor, is shut down traps fluid pressure therein which is immediately available upon engine starting. The manner of accomplishing this useful anddesirable result will be better appreciated upon reference to the following detailed description taken in conjunction with the single figure of the accompanying drawing, inwhich the pertinent portions of the fluid'operated engine agovernor are shown schematically and in section with the unique auxiliary accumulatorapplied thereto L I.The engine governor so far as cut invention comprises first ofall. a fluid pump 2 which has its "alternate inlet sides connected by the conduits 4, 6, and 8 tea sump 10. In each of the conduits 6 toward the lower ends thereof when viewing the drawing arejprovided one-way check valves 12. Depending on the direction of rotation of the pump, the conduits 4 will acteither as a pump inlet or a pump outlet pumping 'inwhich aretwo chambers 24 and 26 in open cornm unication with each other via the passageway 28.,"Each itpertainsto the-pres i ofthe ,chambers 24, 26 is provided with a piston 30 loaded by the ,springsv32. After the ump has'ich'arged any further fluid pressure is relieved in the chambers 24, 26 via the port 34 and piping 36 returning any such excess pressure to the sump 10. The pressure in the chambers 24, 26 of the accumulator 20 is communicated to the upper side 38 of a power piston 40 of the governor via the piping 42. The power piston 40 constitutes a typical engine fuel control means for the fuel racks of the engine (not shown) which racks may be connected to the stem 44 of the piston 40 for example as indicated at 46. Fluid under pressure may also be supplied from the chambers 24 and 26 of the accumulator 20 via the piping 42 and 48 to a port 50 of the governor pilot valve 52. The governor pilot valve 52 is moved axially in a typical manner by the position of the flyweights54 acting against the plate and bearing assembly 56 to which the pilot valve 52 is attached and in opposition to the action of a governor compensating spring 58. The carrier 60 for the flyweights 54 is driven by the engine for which the governor has been provided and is reflective of the speed thereof. When the speed of the engine is sufliciently slow the pilot valve 52 will move downwardly in slide chamber 62 to connect port 50 with port 65 thereby allowing the pressure supplied from accumulator -20 to port 50 to be applied via piping 66 to the underside 64 of the power piston 40.

The engine may be shut down with the governor by manually operating a valve assembly 68 to connect the underside 64 of piston 40 to the sump 10 via the piping 66 and 70. Alternatively the valve assembly 68 may be opened to connect the underside 64 of power piston 40 to sump 10 by de-energizing the solenoid 72 connected to the valve assembly 68. Very briefly, since it forms no part of thepresent invention,.the governor operation is as follows: Pressure is supplied by the pump 2 to the accumulator 20 which in turn supplies pressure via piping 42 to the upper side 38 of piston 40. If the engine speed is too slow, the flyweights 54 will move inwardly allowing the pilot valve 52 to connect port 50 with port 65. thereby supplying fluid pressure to the underside 64 of the power piston 40. Since the area of the underside 64 of the power piston 40 is greater than the area of the upper side 38, the power piston will move upwardly to increase the fuel supplied to the engine to thereby increase engine speed until the flyweights 54 act to close off the port 65. If, on the other hand, the speed of the engine is too great, the action of the flyweights 54 will cause the pilot valve 52 to move upwardly thereby connecting port 65 with port 74 allowingiiuid to be exhausted from the underside 64 of power piston 40 to the sump '10. By relieving the pressure on the underside 64 of power piston 40, it will move downwardly' reducing the amount offuel supplied to the engine and consequently itsspeed until the flyweights 54 moveinwardly sufiiciently to cause pilot valve 52 to close off port 65. "It will .be appreciated that if the valve means 68 is opened so as to connect the underside 64 of the piston 40 to the sump 10 viathepiping 66 and 70, the piston 40 will move to its. lowermost position thereby completely cutting off the fuel from the engine and shutting it down.

From the description so far it should be clear that the fluid pressure in the chambers 24,26 of the accumulator' 20 will not be maintained uponengine shutdown since the pump 2 discontinues operating and the fiuidunder pressure in chambers 24, 26 is not only connected to the sump 10 via the piping 42, 48, ports 50, 65 and piping 66, butthe pressure te' nds'to leak downwardly through the piping 18 and the pumpvch'eck valves 16 arid l2 backto the sump 10. Further leakage may occur past the power piston 40 directly to: the sump 10 via the piping 66, 70. Because of the con nections of the governor and also the leakage past various of the governor components, the pressure in the chambers 24, 26 of the accumulator 20 is gradually dissipated so that when it is subsequently desired to start the engine there is no pressure immediately available for properly operating the power piston 40. This tends to increase the time required for starting the engine and also may cause overspeeding and hunting thereof.

To obviate the above difliculty, an auxiliary accumulator or governor pressure booster mechanism has been provided which is indicated generally of the numeral 76. This pressure booster 76 is connected to the chamber 24 of accumulator 20 via the piping 78. The accumulator 76 comprises an outer housing 80 in which there is provided a piston 82, which is biased toward an end 84 of housing 80 by a spring 86. The face and the cylindrical surface of the piston toward the end 84 are covered by a diaphragm 88 which has a flange 90 clamped against the seal 92 and between the flanges 94, 96 of the two pieces making up the housing 80. Fixed to the end 84 of housing 80 is an adapter assembly 98 which includes a fitting 100 for connecting an end of piping 78 to a passageway 102 therein. Passageway 102 communicates via passageway 104, ch-amber106, and another passageway 108 to the face'110 of the piston 82. Passageway 104 leading to chamber 106 terminates in a valve seat 112 which is adapted to be closed by a valve 114. The stem 116 of valve 114 has connected thereto the armature 118 of a solenoid 120. The valve 114 is norm-ally biased to a closed position by a spring 122 whose action, however, may be overcome by energization of the coil 124 of solenoid 120. The solenoid 120 may be energized by closure of switching means. 126 which is connected in series with a voltage source.

such as the battery 128 and the operating ooil 1 24 of solenoid 120. The solenoid 120 is also connected in series with solenoid 72 for operating the valve means 68. The switch 126, of course, may be either manually. operated or automatically operated by any suitable means for shut-down of the engine.

The operation of the auxiliary accumulator is .as fol: lows: Assuming the engine to be running and the switch 126 to be closed, the solenoid 120 will maintain the valve 114 open so that the pump 2 will not only charge the chambers 24, 26 of accumulator 20 but via piping 78 will also charge auxiliary accumulator 76. If now the engine should be shut down as for example by opening switch 126, the solenoid 120 will be de-energized and the spring 122 will cause the valve 114 to close thereby trapping fluid pressure in the accumulator 76. If the engine is shut down sufficiently for the pressure to leak 01f or otherwise be dissipated from the, chambers24, 26, the pressure in the accumulator 76 will always be available for subsequent starting of the engine so as to properly operate the engine governor. In other words by the present invention, the immediate pressure thus available will materiallycut down the starting time of the engine (since the power piston by reason of the pressure acting on the underside 64 thereof will im mediately move upwardly in the fuel increasing direction) and there will be immediate governor control after the engine is started thereby-eliminating the danger of overspeeding during starting.

I claim:

1. In an engine governor having a fluid operated engine. fuel control means, an engine-driven fiuidrpump, an accumulator between said pump and control means chargeable bysaid pump for supplying fluid, pressure to said control means, an auxiliary accumulator C011. nected tosaidfirst-mentioned accumulator and also chargeable by said pump through said first-mentioned accumulator, afirst valve means between said first-mentioned accumulator and said auxiliary accumulator. operable to disconnect said auxiliary accumulator, from said first-mentioned accumulator to store fluid pressure 4 therein, a second valve means operable to relieve fluid pressure from said engine fuel control means to effect engine shut down fuel cut-ofi, a first solenoid means associated with and operable to actuate said first valve means to an open pressure supply position, a second solenoid means associated with and operable to actuate said second valve means to control the relievingof fluid-pressure from said engine fuel control means,

a voltage source, and switch means interposed between said voltage source and said solenoid means and operable to selectively control the energization of said solenoid means and thereby the actuation of said first and second valve means to effect engine shut down fuel cut-off and to connect said auxiliary accumulator through said first valve means and said first mentioned accumulator to said fuel control means during engine running operation and for engine starting governor control.

2. In an engine governor having a fluid operated engine power control means including a member movable between a maximum engine speed and power position and an engine shutdown position, an engine-driven fluid pump, an accumulator chargeable by said pump for supplying fluid pressure to said engine power control means, a first valve means between said accumulator and said control means operable to disconnect said accumulater to prevent loss of pressure therefrom, a second valve means operable to relieve fluid pressure from said fluid operated engine power control means to shift said member to its engine shutdown position, and means operably interconnecting said first and second valve means and operable to actuate said first valve means to disconnect said accumulator when said second valve means is actuated to effect engine shutdown movement of said engine power control member and to actuate said first valve means to establish fluid connection between said accumulator and said engine power control means. upon actuation of said second valve means to maintain fluid pressure supplied to said engine power conposition and an engine shutdown control position, an

engine-driven fluid pump, an accumulator chargeable by said pump for supplying fluid pressure to said engine power control. means, valve means between said accumulator and said control means operable to disconnect said accumulator to prevent loss of pressure therefrom, means operable to shift said power control member to its engine shutdown position, and means operably interconnecting said last-mentioned means and said valve means and operable to actuate said valve means to disconnec t sai d accumulator when said power control member'is actuated to its engine shutdown position and to actuate said valve means to establish fluid connection between said accumulator, and said engine power control means upon actuation of said, power control member from its engine shutdown position. I

4. In an engine governor having a fluid operated engine power control means including a member movable between a maximum engine speed and power effecting position and an engine shutdown effecting position, an engine-driven fluid pump, an accumulator chargeable by said pump for supplying fluid pressure to said engine power control meansga first valve means operable to connect said accumulator and said control means and to disconnect said accumulator therefrom to' prevent loss of pressure from said accumulator, a second valve means operablehto relieve fluid pressure from said fluid operated engine power control means thereby causing said member to shift to its engine shutdown position, a voltage source, a first solenoid associated with said first valve means for operation thereofia second solenoid associated with said second; valve means for operation thereof, said first. and second solenoids being in series circuit with mat-llaeach other and said source, and switching means in said series circuit selectivelyoperable to de-energize said first and second solenods to actuate said first valve means to disconnect said accumulator and to actuate said second valve means to relieve fluid pressure from said power control means thereby effecting engine shutdown movement of said engine power control member and said switching means being selectively operable to energize said first and second solenoids to actuate said first valve means to establish fluid connection between said accu- 5 References Cited in the file of this patent UNITED STATES PATENTS Kalin June 26, 1945 Greer et al. May 6, 1952 Treganowan Nov. 18, 1952 Jelinek June 9, 1953 

